Las Vegas mayor Oscar Goodman appears near the end of the episode 'Early Rollout' (Season 4, Episode 15) in an uncredited role as a murder suspect's attorney. Before becoming mayor of Las Vegas, Mayor Goodman was a practicing attorney. Among his clients, he represented several notorious 'mob' figures from days gone by referred to on the show as 'Old Vegas' or 'Back in the Day.'

Oscar Goodman, still a practicing attorney in 1995, portrayed himself in the movie "Casino." He was elected mayor of Las Vegas in 1997.

David Berman, who plays assistant coroner David Phillips, is also the chief researcher for the show.

Robert David Hall, who plays Chief Medical Examiner Dr. Al Robbins, actually does need the crutch he uses to walk with. The actor is a double amputee and has two prosthetic legs. His injuries resulted from an accident in the late 1970s.

Chief Medical Examiner, Dr. Al Robbins keeps a photo album of the corpses of famous people who have been laid out in his morgue.

While most of the science depicted on CSI is more or less accurate, the most unrealistic 'science' on the show is the purported enhancement of video. This is particularly true where they 'enhance' an image from a very small portion of a video frame. In one episode, a license plate is able to be read out of the reflection in someone's eye on a picture taken from a cell phone camera. Given the low resolution of most cellphone cameras, such a reflection might only consist of 16 to 32 pixels. This is hardly sufficient to be able to derive a clearly visible license plate from. The same is true from surveillance videos, particularly from non-casino sources. Surveillance videos are typically low resolution in order to lower the cost of the surveillance equipment.

On CSI, DNA results are typically returned within an hour or two. In reality, many DNA tests may take several days to over a week to produce results.

The CSI franchise uses excerpts from works from "The Who" for theme songs. The franchise has paid their respects to The Who by having Roger Daltrey, lead singer of The Who, as a special guest star in the episode "Living Legend" (Season 7, Episode 9) where he plays a mob figure who disappeared in 1976 and his body was never found.

In addition, John Entwistle, bass player for The Who, is mentioned as being in Dr. Robbins' corpse photo album of famous persons that he's had on his slab. ("Room Service." Season 6, Episode 2) Entwistle died in Las Vegas in 2002 of cardiac arrest induced by the consumption of cocaine.

One of the properties owned by Sam Braun is The Tangiers. The Tangiers was also the name of the property that the movie "Casino" revolved around.

William Petersen named his character after astronaut Virgil 'Gus' Grissom, an astronaut who died in the tragic Apollo 1 fire in the late 1960s. The character's name was originally to be Gil Scheinbaum, but the producers decided that casting William Petersen as a Jewish character was a bit too much of a stretch.

The first season was shot and broadcast in the traditional television aspect ratio of 4:3. Beginning is season 2, the format was changed to HD.

In the first season, the show had its own custom developed theme. Beginning with season 2 the Who's "Who are you?" became the basis of the show's theme. The CSI spin-offs (Miami & NY) all use selections from the Who as the basis of their shows' themes.